Manitowoc 2250 Service And Maintenance Manual

Reference Only
INTRODUCTION 2250 SERVICE/MAINTENANCE MANUAL
1-40
Published 11-06-15, Control # 040-13
Swing System Operation
NOTE: References to “swing lock” are for past production
cranes as the swing lock is disabled on current
production.
General
See Figure 1-21 and Figure 1-22 for the following procedure.
One hydraulic swing pump drives one swing motor (optional
swing drive has one swing pump driving two swing motors).
The swing system is controlled with swing control handle
movement and the PC. The swing control handle is
inoperable when swing brake is applied or the swing lock is
engaged. The motor driven swing gearbox drives a tooth
gear that is meshed with undercarriage turntable bearing to
swing the rotating bed.
The swing motor is controlled directly by the output fluid
volume of the swing pump. The PC does not control the fixed
displacement swing motor. Swing pressure senders monitor
the pressure on swing left and swing right sides of swing
closed loop system. If there is low swing pressure or if either
pressure sender fails, swing movement may be erratic.
The rotating bed is free to coast if swing control handle is in
neutral position, swing brake is released, and swing lock is
disengaged.
When swing control handle is moved from off, an input signal
is sent to the PC. The PC sends a 12 volt output signal to
enable the optional swing/travel alarm. When swing control
handle is moved to off, the PC sends a 0 volt output signal to
disable the swing/travel alarm.
An orifice across swing pump and motor ports A and B allow
smoother fluid flow when shifting the swing from one
direction to the other.
Swing speed and swing torque can be selected for type of
work being performed by referring to Speeds screen in
Crane Diagnostics in Section 10 of this manual.
Swing Brake and Swing Holding Brake
The swing system has a spring-applied hydraulically
released brake on drive shaft.
Pilot charge pressure from boom hoist charge pump must be
about 250 psi (17 bar) for full release of swing brake and
swing lock. If system charge pressure is below 190 psi (13
bar), swing brake or swing lock could be partially applied and
damage the swing system. If brake pressure or electrical
power is lost when operating, the swing brake is applied.
When the swing brake switch in off position, an input voltage
is sent to enable swing brake solenoid valve HS-7. Swing
brake solenoid valve shifts to block tank port and opens port
to supply hydraulic fluid to release swing brake from shaft.
When the swing brake switch is placed in on position, an
input voltage is sent to disable swing brake solenoid valve
HS-7. The brake solenoid valve shifts to close fluid flow to
brake and opens tank port to apply the brake.
Swing holding brake switch is located on the side of swing
control handle. To prevent damage to swing system, swing
holding brake switch must only be applied when crane is at a
standstill.
When holding brake switch is pressed in and held, an input
voltage is sent to disable shift swing brake solenoid HS-7.
Swing brake valve shifts to block fluid to brake and swing
brake is applied.
When swing holding brake switch is released, an input
voltage is sent to enable shift swing brake solenoid HS-7.
Swing brake valve shifts, allowing system pressure to
hydraulically release brake.
Swing Lock (Past Production)
The swing lock is a mechanical brake that places locking
pins into slots in shaft locking flange of gearbox.
When swing lock switch is placed in disengaged position, an
input signal is sent to enable disengage solenoid valve HS-9
and a 0 volt output to disable engage solenoid valve HS-8.
Swing lock valves shifts to supply pilot pressure from boom
hoist charge pump to rod end of swing lock cylinder. Fluid
from the piston end of swing lock cylinder exhausts to tank
through swing lock solenoid valve. The cylinder retracts,
disengaging mechanical locking pins from slots in shaft
locking flange, allowing crane to swing in either direction
when swing motor brake is released.
When swing lock switch is placed in engaged position, an
input signal is sent to disable solenoid valve HS-9 and to
enable HS-8. Swing lock valve shifts to supply pilot pressure
from boom hoist charge pump to piston end of swing lock
cylinder. Fluid from rod end of swing lock cylinder exhausts
to tank through swing lock solenoid valve. The cylinder
extends, to engage mechanical locking pins into shaft
locking flange.
Swing Right or Left
When swing control handle is moved to the left, an input
voltage of 5 volts or more is sent to the PC. The PC sends a
variable plus 0 to 2.8 volt output that is applied to swing
pump EDC. Pump EDC tilts swashplate relative to control
handle movement. Fluid flows from pump ports to motor
ports, turning rotating bed to the left.
When swing control handle is moved to right, an input
voltage of 5 volts or less is sent to the PC. The PC sends a
variable minus 0 to 2.8 volt output that is applied to swing
pump EDC. Pump EDC tilts swashplate relative to control
handle movement. Fluid flows from pump ports to motor
ports, turning rotating bed to the right.
As swing control handle is moved to neutral position, the PC
compensates for hydraulic system leakage or changing

Manitowoc 2250 Specifications

General

Brand	Manitowoc
Model	2250
Category	Construction Equipment
Language	English